1. Field of the Invention
The present invention relates to a picture recording device which records main picture data obtained by photographing onto a recording medium, and more specifically, relates to a technique shortening time necessary to display when a picture id selected in reproduction mode.
2. Description of the Related Art
In recent years, many digital cameras have been commercialized and widespread at home. Most of digital cameras have display units such as LCD (Liquid Crystal Display) so as to be able to check a photographed picture on the spot.
In recording processing of a digital camera, picture data obtained by photoelectric conversion is recorded onto a recording medium (portable recording medium) such as a semiconductor memory by performing compression processing. JPEG (Joint Photographic Experts Group) is typically applied as compression processing. Two kinds of picture data including main picture data where the number of pixels is set before photographing and thumbnail picture data with picture size smaller than that of the main picture data are recorded into a file.
In reproduction processing of a digital camera, arbitrary picture data is selected from a plurality of pieces of picture data recorded onto a recording medium, and the selected picture data is resized to display size to be displayed on the display unit of the camera body. Alternatively, display picture data including a group of pictures obtained through pasting a plurality of pieces of picture data recorded onto a recording medium on a display frame region is displayed on the display unit of the camera body.
A conventional digital camera typically uses picture data recorded onto a recording medium in reproducing and displaying. It is necessary to increase the number of pixels for recording picture data of higher resolution. According to the advancement of image pickup devices and the like, the number of pixels is increasing year by year. In proportion to it, a size of a picture file recorded onto a recording medium is also increasing.
As a result, time and load required for reading processing, extension processing and picture resize processing of main picture data with high-definition from a recording medium are increasing. When a picture is selected in reproduction mode, it cannot be displayed immediately. A sense of discomfort in operation cannot be erased because picture is not displayed soon even if it is selected in reproduction mode. When display is changed, since time for reproduction processing of picture data displayed next is required, picture data cannot be selected quickly.
There is a digital camera that can change picture data quickly by displaying thumbnail picture data in place of main picture data. The thumbnail picture data has a picture quality lower than that of the main picture data with high-definition.
Further, there is a devised configuration in which picture display of thumbnail picture data is performed first, extension processing of main picture data is performed during the display, and display is changed from the thumbnail picture data to the main picture data when extension processing of the main picture data is completed. However, the main picture data is handled also in this improvement. Thus it is difficult to reduce load.
Except the example described above, as illustrated in Japanese laid-open patent document (Japanese Patent Application Laid-Open (JP-A) No. 2005-236496), there is also a devised configuration in which display picture data matched with display size is stored aside from main picture data and thumbnail picture data, and then the display picture data is displayed after performing extension processing thereto. However, it takes long time to read the display picture data from a recording medium. Since picture data is recorded onto a recording medium in this configuration, the number of pictures recorded onto the recording medium is reduced.
Aside from reproduction of one picture, in reproduction of display picture data including a group of pictures, since a plurality of pieces of picture data are read from a recording medium and then are pasted on the display frame region for display, reading processing of picture data equal to number of pieces displayed on one screen from the recording medium, extension processing of the read picture data, and resize processing to arbitrary size have to be performed. It takes long time as in reproduction of one picture.